This relates generally to electronic devices, and more particularly, to electronic devices with displays.
Electronic devices often include displays. For example, cellular telephones and portable computers may have displays for presenting information to a user.
Liquid crystal displays contain a layer of liquid crystal material. Pixels in a liquid crystal display contain thin-film transistors and electrodes for applying electric fields to the liquid crystal material. The strength of the electric field in a pixel controls the polarization state of the liquid crystal material and thereby adjusts the brightness of the pixel.
Substrate layers such as color filter layers and thin-film transistor layers are used in liquid crystal displays. A thin-film transistor layer contains an array of the thin-film transistors that are used in controlling the electric fields in the liquid crystal layer. A color filter layer contains an array of color filter elements. The color filter layer provides the display with the ability to display color images. In an assembled display, the layer of liquid crystal material is sandwiched between the thin-film transistor layer and the color filter layer.
Other displays such as organic light-emitting diode displays may also have color filter layers. For example, an organic light-emitting diode display that has an array of white light diodes may use a color filter layer to impart colors to the light from the white light diodes.
Color filter layer arrays typically contain red, green, and blue color filter elements. The use of only three colors in a color filter layer restricts the color gamut that may be produced by the display. To enhance color gamut and enhance the overall transmittance of the color filter layer, additional colors may be incorporated into the color filter layer. For example, the color filter layer may be formed from color filter elements of six different colors.
Fabricating color filter layers with large numbers of color filter element colors can be challenging. Color filter elements are generally formed by depositing blanket layers of colored photoimageable polymer that are patterned photolithographically to form desired color filter element patterns. If care is not taken, an excessive number of processing steps may be needed to form the color filter elements in a color filter layer with more than three different colors.
It would therefore be desirable to be able to provide improved color filter layer arrangements for electronic devices with color displays.